When scientists first decoded the human genome in 2000, they were
quick to portray it as proof of humankind's remarkable similarity. The
DNA of any two people, they emphasized, is at least 99 percent
identical.

But new research is increasingly exploring the
remaining fraction to explain differences between people of different
continental origins.

Scientists, for instance, have recently
identified the small changes in DNA that account for the pale skin of
Europeans, the tendency of Asians to sweat less and West Africans'
resistance to certain diseases.

At the same time, genetic
information is slipping out of the laboratory and into everyday life,
carrying with it the inescapable message that people of different races
have different DNA. Ancestry tests tell customers what percent of their
genes are from Asia, Europe, Africa and the Americas. The heart-disease
drug BiDil is marketed exclusively to African Americans, who seem
genetically predisposed to respond to it. Jews are offered prenatal
tests for genetic disorders rarely found in other ethnic groups.

Cowardice abounds however. Ed.

Such developments are providing some of the first tangible benefits of
the genetic revolution. Yet some social critics fear they may also be
giving long-discredited racial prejudices a new potency. The notion
that race is more than skin-deep, they fear, could undermine principles
of equal treatment and opportunity that have relied on the presumption
that we are all created equal.